The present invention relates to a boot guard for preventing contact between the concrete poured into the bottom of a manhole construction and the flexible joint connection between a sewer conduit and manhole wall opening.
Sewer manhole constructions have been used for many years for providing ample space to clean or open clogged sewers. They are usually placed at intervals of 300-500 feet with a straight line portion of the sewer extending between a pair of adjacent manholes. Usually, the manhole enlarges to about four feet in diameter and continues at this diameter down to the sewer elevation. The sewage is carried through the manhole floor in channels in the floor with the depth of the channels being up to the full diameter of the sewer conduit ends which extend into the manhole.
A quantity of concrete is normally poured into the bottom of the manhole construction up to and adjacent the side wall openings which receive the sewer conduits to provide a flooring for the bottom section of the manhole. Conventionally, one or more U-shaped channels are formed in the top surface of the flooring which communicate with respective inlet and outlet ends of the sewer conduits so that sewage from the sewer conduits flows in the channels in the bottom of the flooring through the manhole construction and outwardly thereof.
Thus, after a manhole construction is placed within the ground with the sewer conduits connected thereto, it is conventional to pour concrete into it and form channels between the open ends of the sewer conduits for permitting the sewage to be carried through the manhole. Since it is important that the flexible joint or seal between the sewer conduit and manhole wall opening remain flexible, something must be done to prevent poured concrete from engaging the flexible joint connection between the sewer conduit and manhole wall opening. Further, it is not desirable that concrete be poured against the end of the sewer conduit or against the flexible joint connection because removal of the sewer conduit for repair or replacement is made much more difficult.
Heretofore, when the concrete was poured into the bottom of the manhole construction, a gap was formed between the concrete that was poured into the bottom of the manhole and the ends of the sewer conduits extending into the manhole. This procedure for preventing contact between the poured concrete and flexible joint for protecting the flexibilty of the pipe joint and permitting removal involves considerable time and effort and, therefore, is expensive.
Thus, there has been a need for an inexpensive means for preventing contact between the poured concrete and flexible joint connection between a sewer conduit and manhole wall opening.